If you remove one from eleven, it becomes ten. If you remove one from nine, it becomes ten.

How is this possible?

If eleven plus two equals one, what does nine plus five equal?

How many sides does a circle have?

In two decks of cards, what is the least amount of cards you must take to be *guaranteed* at least one four-of-a-kind?

What has many keys but can’t open a single lock?

A boy and a girl are sitting on the porch.
"I'm a boy," says the child with black hair.
"I'm a girl," says the child with red hair.
If at least one of them is lying, who is which?

In order to complete the racing competition, the Mexico racetrack has to submit its top and the most famous three horses to win the competition. Due to an electrical storm, all the records are cleared and no one knows which horse holds the record. They all look identical and it becomes even more difficult to differentiate the horses. There are 25 horses in the Mexico racetrack. But there can be only five horses at a time on the track. What will the least number of races that can be conducted to find out the three fastest horses?

We know that the number 7 is the prime followed by a cube. Which next number is also a prime followed by a cube?

How many triangles are there on the puzzle below?

Below is the sum of symbols in each row and column in the figure. Analyzing the figure, can you find out the value of the symbols?